Cam selector mechanism in an ornamental stitch sewing machine



Sept. 30, 1969 MAsAo TAJIMA 3.469,547

CAM SELECTOR MECHANISM IN AN ORNAMENTAL STITCH SEWING MACHINE Filed Dec. 12. 196e v 2 sheets-sheet 1 INVENTOR- Witness Mosao Tojma 14ml/5nd Teal ,TTORNEY 4 Sept. 30, 1969 MAsAo TAJIMA CAM SELECTOR MEGHANISM 1N AN ORNAMENTAL STITCH SEWING MACHINE Filed DBC. l2, 1966 2 Sheets-Sheet 2 y Masao Tajma ATTORNEY United States Patent O 3,469,547 CAM SELECTOR MECHANISM IN AN ORNA- MENTAL STITCH SEWING MACHINE Masao Tajima, Utsunomiya, Tochigi, Japan, assignor to The Singer Company, New York, N.Y., a corporation of New Jersey Filed Dec. 12, 1966, Ser. No. 601,151 Int. Cl. Db 3/02 U.S. Cl. 112--158 7 Claims ABSTRACT 0F THE DISCLOSURE This invention relates to ornamental stitch sewing machines and in particular to a novel and improved mechanism whereby one of a plurality of pattern forming discs may be selected to transmit a predetermined needle-jogging motion by way of a cam follower and transmission means so that the needle is transversely shifted in conformance with the pattern sensed by the cam follower and thereby resulting in the desired stitch pattern.

The conventional type of ornamental stitch pattern forming device generally has required a relatively complicated arrangement of components thus resulting in a comparatively complicated mode of operation. Exemplary of such prior art devices are those which rely upon the use of a plurality of pattern cams having a plurality of independently operable cam scanning fingers or cam followers wherein the pattern control switch or switches for rendering selected cam followers effective are stationarily mounted on the machine frame. This latter prior art expedient necessarily requires a relatively complicated arrangement of components for stationary mounting on the machine frame and also so that relative movement of the cam discs and control switches is precluded while allowing movement of the cam followers or scanning fingers. The present invention overcomes not only these, but other prior art deficiencies which will be readily apparent from the following description by providing a cam selector device comprising a relatively simple lever arrangement and mode of operation wherein the control selection lever or switch oscillates in conformance with the motion of the pattern sewing cam followers. The present invention has a further advantage in that it is not mounted on the machine frame and thus can be readily mounted on a machine having a single cam pattern disc as will be apparent from the following descrip.

tion.

Accordingly, it is a primary object of the present invention to provide in a sewing machine a novel and improved ornamental stitch forming mechanism that is simple, efficient and dependable and which will produce preferably, either a stitch-by-stitch zigzag or blend stitch pattern of needle-jogging upon actuation of a control lever or switch.

Another object is to provide in a zigzag sewing machine a needle-jogging mechanism comprising a plurality of pattern cam discs having control means for selectively engaging a cam follower which senses the pattern of one of the said cam discs and transmits this sensed pattern to the needle of the sewing machine thereby causing said needle to transversely shift in conformance with the sensed pattern.

It is a further object of this invention to provide a readily accessible control actuation means for enabling selection of the desired ornamental stitch pattern by coaction of a plurality of different patterned cams and corresponding number of tracking means through the medium of a very simple lever operation.

A further object is to provide a cam selector mecha- ICC nism that is so constructed and arranged that it can be easily and economically mounted onto a machine which already has a single cam pattern disc thereby providing a plurality of different stitch pattern cams having selection control means therefor.

Still yet another object of this invention is to provide a control means which is so constructed and arranged with reference to the cam follower means so that the former oscillates in conformance with the pattern sensed by said cam follower means thereby allowing for use of a relatively simple lever arrangement to produce the resultant desired ornamental stitch pattern.

Having in mind the above and other objects that will be evident from an understanding of this disclosure, the invention comprises the devices, combinations and arrangements of parts as illustrated in the presently preferred embodiment of the invention which is hereinafter set forth in such detail as to enable those skilled in the art readily to understand the functions, operation, construction and advantages of it when read in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of the cam selector mechanism and associated components for producing the desired needle-jogging motion constructed in accordance with the present invention;

FIG. 2 is a detailed partial front elevational view of the control member and the cam follower associated therewith seen in FIG. 1;

FIG. 3 is a detailed schematic perspective view of the cam control and selector mechanism seen in FIG. 1;

FIG. 4 is an enlarged detailed View of the components which comprise the cam selector land control mechanism; and

FIG. 5 is a front elevational view of a sewing machine embodying this invention.

Referring now to the accompanying drawings wherein like reference numerals designate similar parts throughout the various views, the preferred embodiment of this present invention is shown incorporated in a family sewing machine for straight, zigzag or blind stitching such as the Singer machine No. 223. The sewing machine illustrated has a bed-plate 62 affording a work support from one end of which rises a standard 63 integrally formed with a bracket arm 60 overhanging the bed-plate and terminating at its free end in a head 61. As illustrated in FIG. 5, a cam selector lever 40 for the cam selector mechanism of this invention is located in the arm 60 behind a front plate 64 which has a pair of holes therein for receiving the shafts respectively connecting alever 40 and a needle vibrator amplitude regulating knob 50 to their associated components situated internally of the arm 60.

The needle-jogging mechanism includes a cam 1 for generating the zigzag moti-on of a needle 20, and a coaxially mounted cam 2 for generating blind stitch motion in which a needle forms single zigzag stitches between groups of straight stitches, the cams -being iixedly mounted contiguous to each other on a driving cam shaft 3. As `seen in FIG. 4, pins 32 together with plate 31 hold the cams in place on a shaft 3. The cam shaft 3 is turned by a horizontally disposed main arm shaft 25 rotatably journaled in suitable bearings provided in the bracket-arm 60. At the end ofthe shaft 2S opposite from the driving pulley is a counter-balanced crank 26 connected by a link 27 to a collar 28 secured on a vertically disposed needle-bar 21. A presser-bar 29 and presser-foot 30 oppose the work engaging portion of a lower feeding mechanism (not shown) in a conventional manner. The generated motion of the needle selectively produces either a zigzag or blind stitch pattern in accordance with the traced surface of the selected cam. The cam selector mechanism indicated generally at 55 is mounted on a rock shaft 4 which is connected to a needle gate 23 by way of a rock arm 5 having a slideway or groove 6, and a rod 7 connecting a slideblock 8 in the slideway to a pitman 24. The rock shaft is arranged in substantially parallel relation to the cam shaft 3 and a control shaft 16. The tracked pattern is transmitted to the needle gate 23 by way of this structure. The mechanism 55 comprises a first bell crank 9 having a cam follower arm 10, a cam follower or scanning finger 10' and a floating arm 11 fxedly connected to the rock shaft 4 by means of a screw 33 with the cam follower arm aligned with the zigzag cam 1, and `a second bell crank 12 having a cam follower arm 13, a cam follower or scanning finger 13 and a floating arm 14 pivotally mounted on the rock shaft 4 with the cam follower arm in line with the blind stitch cam 2. As screw 35 prevents axial movement of the cranks 9 and 12 along the shaft 4. The bell cranks are scissorlike in shape and are biased by a torsion spring so that the cam follower arms are either in substantially side-byside matched position as shown in FIG. l or have an angle therebetween as shown in FIG. 3. Torsion spring 15 is installed on an Unthreaded portion 36 of a shouldered screw with one spring end 37 hooked onto a pin 38 located on the cam follower arm 13 of the bell crank 12 and the other spring end 39 being hooked onto the side of the floating arm 11 of the bell crank 9. With the torsion spring 15 so arranged, the spring end 39 exerts a counterclockwise rotating force centered around the rock shaft 4 which is applied to the cam follower 10 of the bell crank 9 and the spring end 37 exerts a clockwise force centered around the rock shaft 4 which is applied to the cam follower 13 of the bell crank 12 by virtue of the spring end 37 being hooked onto the pin 38 located on the cam follower arm 13 of the latter bell crank. Thus, the floating arm 14 of the bell crank 12 is urged upwardly against one of the sides 41 or 42 of a control member or plate 17. The bell cranks 9 and 12 and thus, their respective cam followers 10 and 13' are biased into engagement with the corresponding cams 1 and 2 in a conventional manner by a spring 53 fastened at one end to the machine frame (not shown) and acting through the needle bar gate 23, which the spring urges to the left (see FIG. l), the pitman 24, the rod 7, the rock arm 5 and the rock shaft 4, which mounts the bell cranks 9 and 12 and is biased counterclockwise as shown in FIG. l. The control shaft 16 is journaled in the free end of the floating arm of the zigzag bell crank 9 and is held in position by a snap ring 34, and the control plate 17 which is xedly mounted lon the control shaft bears against the free end of the floating arm 14 of the blind stitch bell crank 12.

The control plate 17 for cam selection, as shown in FIG.

cam selection lever is manually rotated to one of two positions, as shown in FIG. 3, i.e., a position indicated at D in which the zigzag stitch pattern will be effected or a position indicated at E wherein a blind stitch pattern will be obtained. The relative positions of the control plate 17 and the bell crank 12 are clearly illustrated in FIG. 2 wherein the position shown by the dotted lines corresponds to position D of lever 40 shown in FIG. 3 thereby causing a selection of the zigzag cam 1 and the position shown by the solid lines corresponds to position E of the lever 40. It is seen that when position D is selected the lip 43 of the control member 17 `abuts against one of the side walls forming the groove 46 in the floating arm of the bell crank 12 and when position E is selected, the lip 44 of the control cam 17 abuts against the outermost edge of the floating arm 14. The cam selection lever 40, which is preferably manually operable, is installed on the front end of the cam control shaft 16 with `a set screw 45 (FIG. 4).

When the control shaft 16 is manually rotated to a position D (FIG. 3)so that the side 41 ofthe control plate 17 contacts the arm 14 of the bell crank 12 thereby allowing the floating arms of the bell cranks to come closet together vertically, only the cam follower 10 of the zigzag bell crank 9 contacts the zigzag cam 1. When the control shaft 16 is manually rotated to a position E (FIG. 3) so that the side 42 of the control plate 17 contacts the arm 14 of the bell crank 12 thereby vertically spreading the floating arms of the bell cranks away from each other as illustrated in FIG. 1, only the cam follower 13 of the blind stitch bell crank 12 contacts the blind stitch cam 2.

The above may be more readily seen by further reference to FIG. 4 in conjunction with FIG. 3. As shown in FIG. 4 the cams 1 and 2 have identical outer diameters A-A and inner diameters B-B' as well as identical concave indentations C-C'. The number of concave indentations C on the blind stitch cam 2 are fewer in number than the concaves C found on the zigzag cam 1. This feature allows for the blind stitch cam 2 to be the controlling cam pattern by filling in a number of the concaves C of the zigzag cam 1 thereby resulting in the pattern traced by the cam follower arm 13 being transmitted to the needle. When the cams are mounted on the cam shaft 3 they are located contiguous to each other and are held in place by pins 32 so that a concave C of the zigzag cam 1 is matched to a concave C of the blind stitch cam 2 as shown by the dotted lines in FIG. 4. This arrangement t0- gether with the fact that the sides 41-42 of the control plate 17 are of different lengths from the control shaft 16 establishes a distance between the cam followers 13 and 10' when the sides 41 of the control plate 17 contacts the floating arm 14 which is greater than the depth of C and C'. This feature of the present invention allows for only the cam follower 10 to selectively contact the zigzag cam 1 and thereby produce a zigzag stitch pattern in accordance with the surface of the cam 1 sensed by said follower 10'. When the side 42 of the control plate 17 is in contact with the floating arm 14 of lthe bell crank 12 (position E), the cam follower 13' is in contact with the blind stitch cam 2 whereupon the floating arm 11 of the bell crank 9 is urged slightly upwards in a clockwise direction. This latter movement is caused by the difference in lengths between the side 41 and the control shaft 16, and the side 42 and the control shaft 16. As the control lever 40 is rotated to position E, i.e. side 42 in contact with arm 14, the cam follower 13' contacts the surface of the blind stitch cam 2 before the lip 44 contacts the outermost edge of the floating arm 14, which latter position is the position required of the control plate 17 (position E) in order to select the blind stitch pattern. At this point the bell crank 12 has reached its maximum rotation in the counterclockwise direction, that is, the cam follower 13 has contacted the periphery of the cam 2, while the cam follower 10 is still in contact with the zigzag cam 1. Thus, as the control lever 40 is further rotated in a counterclockwise direction to position =E (with the lip 44 contacting the outer edge of the arm 14) the control shaft 16 is urged upward in a clockwise direction relative to the arm 14 and therefore similarly for the floating arm 11 of the bell crank 9 since it is commonly mounted with :the control shaft 16. Accordingly, this motion causes the cam follower 13 to be controlling and moves the cam follower 10 with a corresponding slight clockwise rotation of the shaft 4 so that it is slightly spaced from the peripheral surface of the zigzag cam 1 by virtue of the slight upward movement of the shaft 16 thereby resulting in a blind stitch pattern conforming to the sensed surface of the blind stitch cam 2. The removal of either of `the cam followers from its corresponding cam when the other selected cam follower is operative avoids excessive wear of the cam surfaces. However, it is apparent that the foregoing preferred embodiment may be designed so that during blind stitch sewing the cam follower 10 remains in the same position in which it was disposed for zigzag sewing since, for blind stitch sewing the bell crank 12 is controlling with the motion of the bell crank 9 coinciding therewith.

The selected stitching pattern is obtained through the transmission of the movement of the cam follower 10 or 13', depending upon which one is selected, to the needle bar 21 through the medium of a rock arm 5 fixed at the end of the rock sh-aft 4 opposite from the bell cranks and including a slide block 8 which is matched to and slides in a slideway 6. An arm link 18 connects the slide block to a conventional stitch width regulator knob 50 by way of a rod 52 and a regulating lever shaft 51. When the slide block is positioned coaxially with the rock shaft 4 by means of :the stitch width regulating knob 50', no motion is imparted to the needle by either of the cams 1 or 2 and the needle forms straight stitches. As the slide block is positioned farther away from the fulcrum of the slideway by adjustment of the stitch width regulator knob 50, the width of the zigzag stitches increases.

From the above, it will be noted that there has been provided by the present invention in the most preferred embodiment thereof, a very simple cam selecting mechanism for producing a desired ornamental stitch pattern in accordance with the surface of the selected cam and having the characteristic of permitting easy manual switchover between, in this instance, preferably a zigzag and blind stitch pattern and also a mechanism which is readily adapted to a sewing machine having a single pattern cam thereby resulting in a selective ornamental stitch pattern forming machine.

INumerous alterations of the structure herein disclosed will suggest themselves to those skilled in the art. However, it is to be understood that the present disclosure relates to a preferred embodiment of my invention which is for purposes of illustration only and not to be construed as a limitation of the invention. All such modifications which do not depart from the spirit of the invention are intended to be included within the scope of the invention.

Having thus set forth the nature of the invention, what I claim is:

1. In a sewing machine having a frame including a bracket-arm, a needle-bar mountedv in said frame for endwise reciprocation and lateral vibration, a main shaft journaled in said frame, at least a pair of stitch-pattern cam discs of different response-producing shape mounted on said frame for rotation about a common axis, means for rotating said cams in synchronism with said needle reciprocating movements, cam follower means for tracking a selected one of said stitch-pattern cams, means operatively connecting said cam follower means to said needlebar whereby the needle-bar is laterally vibrated in conformance with the stitch-pattern sensed by said cam follower means, a control shaft having a main axis vand being carried by said cam follower means, said main axis of said control shaft being spaced from that of said cam follower means, and control means mounted on said control shaft and arranged to be be shifted into a selected one of two positions, said control means coacting with said cam follower means whereby when said control means is placed in a first position one of the cam discs is tracked by said cam follower means to produce a predetermined stitch-pattern in accordance with the response-producing shape of the tracked cam and when said control means is placed in a second position said cam follower means is disengaged from said one of said cam discs and a different one of said cam discs is tracked by said cam follower means to produce a predetermined stitch-pattern in accordance with the response-producing shape of said tracked cam.

2. In a sewing machine having a frame including a bracket arm, a needle-bar mounted in said frame for endwise reciprocation and lateral vibration, a main shaft journaled in said frame, at least a pair of stitch-pattern cam discs of different response-producing shape mounted on said frame for rotation about a common axis, means for rotating said cams in synchronism with said needle reciprocating movements, cam follower means for tracking a selected one of said stitch-pattern cams, means operatively connecting said cam follower means to said needle-bar whereby the needle-bar is laterally vibrated in conformance with the stitch-pattern sensed by said cam follower means, a control shaft carried by said cam follower means, and control means mounted on said control shaft arranged to be shifted into a selected one of two positions, said control means comprising a control plate having at least two sides disposed at different distances from said control shaft wherein said two sides respectively correspond to a first and a second position, said control means coacting with said cam follower means whereby when said control means is placed in said first position one of the cam discs is tracked by said cam follower means to produce a predetermined stitch-pattern in accordance with the response-producing shaft of the tracked cam and when said control means is placed in said second position said cam follower means is disengaged from said one of said cam discs and a different one of said cam discs is tracked by said cam follower means to produce a predetermined stitch-pattern in accordance with the response-producing shape of said tracked cam.

3. In a sewing machine in accordance with claim 1 including means for mounting said control shaft on said carn follower means so that said control shaft and said control means mounted thereon oscillate in conformance with the selected pattern tracked by said cam follower means.

4. In a sewing machine having a frame including a bracket arm, a needle-bar mounted in said frame for endwise reciprocation and lateral vibration, a main shaft journaled in said frame, at least a pair of stitch-pattern cam discs of different response-producing shape mounted on said frame for rotation about a common axis, means for rotating said cams in synchronism with said needle reciprocating movements, cam follower means comprising at least a pair of cam followers for tracking a selected one of said stitch-pattern cams, means operatively connecting said cam follower means to said needle-bar whereby the needle-bar is laterally vibrated in conformance with the stitch-pattern sensed by said cam follower means, each of said cam followers having a oating arm with a corresponding free end, a control shaft carried by the free end of the floating arm of one of said cam followers, and control means mounted on said control shaft and located at the free end of the floating arm of a second of said cam followers, said control means being arranged to be shifted into a selected one of two positions, said control means coacting with said `cam follower means whereby when said control means is placed in a first position one of the cam discs is tracked by a selected one of said cam followers to produce a predetermined stitch-pattern in accordance with the response-producing shape of the tracked cam and when said control means is placed in a second position said selected one of said cam followers is disengaged from said one of said cam discs and a different one of said cam discs is tracked by a second selected one of said cam followers to produce a predetermined stitch-pattern in accordance with the response-producing shape of said tracked cam. t

5. In a sewing machine in accordance with claim 4 wherein each of said cam followers further includes a cam follower arm arranged transversely of said oating arm, said control means including a control plate having two sides and being adapted to be shifted to a selected one of said two sides, whereby movement to a first side is such that one of said follower arms is effective with its corresponding cam and movement to a second side causes the other of said follower arms to be effective with its corresponding cam.

6. In a sewing machine in accordance with claim 1 and further comprising tension means coacting with said control means and operatively biasing said cam follower means so that said cam follower means is differently orientated in each of said positions.

7. lIn a sewing machine having a frame including a bracket-arm, a needle-bar mounted in said frame for endwise reciprocation and lateral vibration, a main shaft journaled in said frame, at least a pair of stitch-pattern cam discs of different response-producing shape mounted on said frame for rotation about a common axis, means for rotating said cams in synchronisrn with said needle reciprocating movements, selectively shiftable cam follower means corresponding to each of said cam discs for tracking a selected one of said stitch-pattern cams, means operatively connecting said cam follower means to said needle-bar whereby the needle-bar is laterally vibrated in conformance with the selected stitch-pattern sensed by said cam follower means, a control element operably connected with said cam follower means for selecting the desired cam disc stitch-pattern, and control means operably associated with said control element and arranged to be shifted into a selected one of two positions, said control means coacting with and having an axis separate from that of said cam follower means, said control means being constructed and arranged such that it is substantially xedly mounted in its axial disposition, whereby when said control means is placed in a first position one of the cam discs is tracked by said cam follower means to produce a predetermined stitch-pattern in accordance with the response-producing shape of the tracked cam, and when said control means is placed in a second position said cam follower means becomes inoperable relative to said one of said cam discs and a different one of said cam discs is tracked by said cam follower means to produce a predetermined stitch-pattern in accordance with the response-producing shape of said tracked cam.

References Cited UNITED STATES PATENTS RICHARD I. SCANLAN, JR., Primary Examiner 

